The Effects, Problems And Strategies Of Conservation Tillage In Northern Arid Region Of China

In northern arid area of China there are many problems which have restricted the development of economy and society such as environmental deterioration, frequently occurred dust storm, cropland soil wind erosion and lower agricultural productivity. In order to study the effects of conservation tillage on resolving these problems, the economic, social and ecological benefit of conservation tillage in the 24 test regions in the North of China have been investigated. The results were as follows: 1. Multi effects were found in conservation tillage: (1) Conservation tillage can prevent soil wind erosion. The suspension transport granules (dia.<0.05mm) percentage in tibba, grassland, fields with traditional and conservation tillage were 0.62%, 18.99%, 30.87%, 28.76%, respectively. The conservation tillage can reduce soil wind erosion to 14-88% in different conditions. It confirmed that the uncovered cropland and degenerate grassland are the source of the dust storm. (2) Studies on soil characters showed that soil water content and nutrition status increased and surface layer temperature decreased. It indicated that conservation tillage had positive and negative effects on soil economy, but the total effects were in favor of cropland economy conservation and crop growth. (3) Yield of main crops in north China were improved in conservation tillage condition. Thereinto the amplitude of melon is the biggest (24.19%) while the amplitude of wheat is the smallest (5%); Different types of maize under conservation tillage usually got higher yield than those under conventional tillage and the amplitude is 8.2% in average. Under conservation tillage, the deep- plough gained a 28.41% yield improvement and no-till 14.97%. (4) Various degrees of costs saving and benefits increasing were showed in conservation tillage in several crops, especially in economic crops. For example malting barley under conservation tillage can save costs with 70~110yuan/666.7m~2 and increase benefits with 84.54yuan/666.7m~2. To sum up, conservation tillage can evidently improve the yield of crops, save costs and increase benefit.2, There are a lot of problems which limited development of conservational tillage in northern arid area of China. The technical problems showed that: First, technical system was unperfected, and the countermeasure is to take advantage of agriculture technical be break the tradition cultivate form; Second, the soil temperature was low, and the countermeasure is to select appropriate cultivars and employ deep plough to compensate it; Third, weeds controlling were difficult, and the countermeasure is to use integrative methods of biological, chemical and agronomical ways to prevent and cure the weed spread. Propagandizing and government sustaining are the must to cope with the cognition problems on conservation tillage. The policy problems were that rudimentary changes were not occurred in policy and conditions, government must take charge of the project, establish an integrative service system of research, education, spreading, and promote the application and spreading of conservational tillage technologies.